Sam Saprunoff wrote:
> Hello everyone,
> I was curious... Are the uCsimm I/O pins 5V Tolerant? I have been unable to
> verify this from searching through the uCsimm manual (Vdd -0.5 to +4.0,
> Vin -0.5 to +7.0), nor the Motorola MC68EZ328 users manual (Vdd/Vin -0.3 to
> Thanks in advance!
No, they are not. You must use a logic family such as the 74LV which also provides
for voltage level shifting. Nothing in the 68EZ328 User Manual says anything either
way regarding the voltages on the i/o (and other) pins, as it usually happens,
attaching a voltage higher than that of the the specified supply of A processor,
generally results in damage to the pin through long term use.
I would certainly welcome being wrong on this issue, but as yet, I have read no
definitive documentation that specifically addresses the issue of TTL family
interfacing. Rule of thumb? If they don't spec it, don't believe it!
-- Tom Walsh - WN3L - Embedded Systems Consultant - tom over_at mytoys(.)com 'www.mytoys.com', 'www.openhardware.net', 'www.cyberiansoftware.com' "Windows? No thanks, I have work to do..."
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